System and method for controlling jobs of a production device

ABSTRACT

The invention relates to a system and a method for controlling jobs of a production device. The aim of the invention is to allow a current situation to be analyzed and the required operations to be planned, executed, and monitored irrespective of mathematical routines for optimizing the throughput. Said aim is achieved by the fact that a simulated image is formed starting from an initial situation based on real resources and real jobs, a potential sequence of jobs is optimized based on the initial situation regarding available resources and available jobs with the aid of an optimization algorithm, and the production device is controlled with the aid of a solution algorithm such that a target state is determined by simulating the required operations of the production device.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International ApplicationNo. PCT/EP2004/000810, filed Jan. 29, 2004 and claims the benefitthereof. The International Application claims the benefits of Germanapplication No. 10305344.1, filed Feb. 10, 2003, both applications areincorporated by reference herein in their entirety.

FIELD OF INVENTION

The invention relates to a system and also a method for controlling jobsof a production device.

BACKGROUND OF THE INVENTION

A system of this type is employed in the field of automation technology,for example, in order to achieve the most optimum throughput possiblefor a production device or an entire production system consisting of aplurality of production devices. In this respect, the problem frequentlyarises of managing a plurality of jobs, which are also called tasks inthe following, in the production device or production system in such away that the available resources, i.e. the available individual modulesof the production device or production system, are utilized in the mostefficient manner possible and at the same time the shortest possiblerunning time of the jobs and tasks can be obtained. This problem ofoptimum utilization is also referred to as “job-shop scheduling”.

A device and a method for generating adaptive workflows are known fromWO 00/38091. In this respect, individual job sequences are adapteddynamically to a changing work environment with the aid of a scheduleplanner and assigned work procedure instructions. If a control deviceidentifies divergences in this respect, then the work procedures ofuncompleted jobs can be re-assembled. Monitoring means are provided inthis respect, which contain a virtual image of the physical environment.

SUMMARY OF THE INVENTION

The object underlying the invention is to specify a system and also amethod which enables the analysis of the current situation, the planningof the necessary operations, and also the implementation and monitoringof same, in particular also independently of mathematical routines foroptimizing the throughput.

This object is achieved by means of a system for controlling jobs of aproduction device, with a data processing device, which displaysplanning means for determining a possible optimum sequence of the jobson the basis of an initial situation with regard to existing resourcesand existing jobs with the aid of an optimization algorithm, andprocedure control means for coordinating the control of the productiondevice with the aid of a solution algorithm, which is provided forascertaining a target state by simulating the necessary operations ofthe production device.

This object is further achieved by means of a method for controllingjobs of a production device, where a simulated image is formed startingfrom an initial situation based on real resources and real jobs, where apossible optimum sequence of the jobs is formed on the basis of theinitial situation with regard to existing resources and existing jobswith the aid of an optimization algorithm, and where the productiondevice is controlled with the aid of a solution algorithm in such a waythat a target state is ascertained by simulating the necessaryoperations of the production device.

Underlying the invention is the finding that production devices orproduction systems are frequently also subjected to major changes in arelatively short period. For this reason, a simulated image of the realcircumstances is generated in the present method starting in the firstinstance from the initial situation, which is based on the realresources and the real jobs. On the basis of this initial situation, apossible optimum sequence of the jobs is formed with the aid of anoptimization algorithm in the following stage.

The order of the jobs ascertained in this way, in the form of sequences,is then verified by means of the solution algorithm, which attempts toachieve a predefinable target state by simulating the necessaryoperations of the production device. The resultant modularity of thesolution gives rise to a generic solution to scheduling jobs which canalso be adapted in a simple manner to changes in the production deviceor production system. An essential aspect in this respect is that themethod for analyzing the current situation, and for planning thenecessary operations, and also the implementation and monitoring ofsimulated and also actually executed operations are modular instructure, where the mathematical routines for optimizing the throughputare independent of them. Overall, this therefore gives rise to aseparation from a concrete problem of optimizing a singular productiondevice, right through to a general method for handling scheduling tasksfor a production device, which may be used both in the local controlarea for plants and also in factory-wide use for coordinating andsafeguarding a manufacturing setup.

A simulated image of a real situation can be generated in a simplemanner by the fact that the system displays initial means for generatingan image of the initial state of the production device with regard toexisting resources and existing jobs.

Advantageous usage scenarios of the system consist in the fact that theproduction device comprises a manufacturing machine, a productionmachine, a manufacturing plant and/or a production plant.

A further improvement in the job control is obtained by the fact thatthe solution algorithm is provided for verifying the possible optimumsequence of the jobs determined by the planning means.

An efficient processing of jobs which are already waiting is obtained bythe fact that the planning means is provided for coordinating thestarting of waiting jobs on the basis of the current situation image,and in particular with the aid of the optimization algorithm.

A further optimization of the planning tasks and the time-relatedcontrol of the job sequences can be effected by the fact that the stagewhere a possible optimum sequence of the jobs is formed on the basis ofthe initial situation with regard to existing resources and existingjobs with the aid of the optimization algorithm is carried out multipletimes.

Desired target states which can be predefined automatically or by theuser with regard to the production device can be taken into account bythe fact that the solution algorithm attempts, on the basis of a givensimulated situation, to achieve a predefinable target state of theproduction device by simulating the necessary operations/stages.

A clear and target-oriented representation of results can be ensured bythe fact that forward-planning operations and responses are determinedin advance through the compilation of an action list which contains allthe actions up to the final evacuation of the plant.

Defective situations can be identified in a simple manner by the factthat the situation is evaluated continuously and new actions are createdfor the elimination/bypassing of problems.

In the following, the invention is described in detail and explained onthe basis of the exemplary embodiments represented in the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic representation of a system for controlling jobsof a production device with an outline diagram of the planning andcontrol tasks, and

FIG. 2 shows a schematic representation of a system for controlling jobswith a link to an operating and monitoring system of a stored-programcontrol unit.

DETAILED DESCRIPTION OF INVENTION

FIG. 1 shows a schematic representation of a system 9 for controllingjobs of a production device 3. In the case of the exemplary embodimentshown in FIG. 1, the production device 3 is characterized by resourcesR1 . . . R3 and also currently existing jobs J1 . . . J3. The system 9for controlling jobs of the production device 3 further includes a dataprocessing device 4, which forms a simulated image 6 of the realproduction device 11. For this purpose, the simulated image 6 of theproduction device 3 includes simulated resources SR1 . . . SR3 and alsosimulated jobs or simulated tasks SJ1, SJ2, SJ3. The schematic outlineof the job control, which exists on the data processing device 4,further includes a planning facility 16 and also a procedure controlunit 17, where the planning facility 16 is also referred to as thescheduler 16 in the following and the procedure control unit 17 also asthe dispatcher 17 in the following. The planning facility 16 coordinatesthe starting of the waiting jobs SJ1 . . . SJ3 or J1 . . . J3 on thebasis of a current situation 18 with the aid of an optimizationalgorithm 12. The procedure control unit 17 coordinates the necessaryactions for secure control of the plant 3. For this purpose, it utilizesa solution algorithm 13, which creates an action list 14 from theresult, which is jointly managed by the procedure-control unit 17. Theaction list 14 contains a list of actions to be implemented A1, A2, etc.for the processing and coordination of the jobs J1 . . . J3.

The basic functioning of the job control for the system represented inFIG. 1 is explained in detail in the following:

starting from the current situation of the real production device 3,consisting of the real resources Rx and the real jobs Jx, a simulatedimage 6 is created, characterized by the simulated resources SRx and thesimulated jobs SJx, which provides the necessary information in the formof the current situation 20 for the job control. In this respect, theunits existing on the data processing device 4, specifically theplanning facility 16 and the procedure control unit 17, comprise twoindependently operating units, where the planning facility 16 isresponsible for the scheduling of new jobs, i.e. for their starting timeand their starting sequence. The procedure control unit 17 takes overthe processing, the distribution and also the forwarding of the jobs.Both units, the planning facility 16 and also the procedure control unit17 require respectively current situation images 18, 19 as necessary,which are derived from the simulated situation 20 as the image of thereal situation.

The planning facility 16 utilizes the current situation 18 firstly forthe purposes of determining a possible optimum job sequence, in linewith the optimization algorithm 12. This sequence is handed over to thesolution algorithm 13 together with the current situation 18, in orderthat the plausibility of the proposed solution can be checked. In linewith the optimization algorithm 12, the stage for determining a jobsequence or the plausibility of the ascertained sequence can be effectedmultiple times. The respectively determined optimum result is forwardedby the planning unit 16 to the procedure control unit 17 via an handoverunit 15 with handover positions ÜP1, ÜPx to the procedure control unit17. The procedure control unit 17 similarly requests the currentsituation 19 of the production device 3 or the plant as necessary, andcalculates a list of the actions to be implemented A1, A2, etc. on thebasis of the solution algorithm 13. However, this list does not justconsist of precisely those necessary actions but similarly contains thefuture stages. The solution algorithm 13 therefore calculates all theactions A1 . . . An for a predefinable target state on the basis of itssimulation rules, for example up to the complete “evacuation” of theproduction facility 3, which involves a semiconductor production devicefor example. Due to the modular structure, with planning means 16 andprocedure control unit 17, and also optimization algorithm 12 andsolution algorithm 13, the solution algorithm 13 is the only part of thesystem which must be adapted in a concrete manner to the respectiveproduction environment or the respective plant.

To the extent that the solution algorithm 13 identifies the fact that asituation is arising in the simulation and in the creation of the actionlist 14 which can no longer be solved, the point at which problems willoccur in the plant or in the production device can already be determinedin advance by the solution algorithm 13 in this case. A user cantherefore already take counter-measures beforehand and therefore preventmalfunctions of the plant which would otherwise arise.

The actions A1 . . . Ax on the action list 14 contain the responseswhich must be triggered by a control unit of the production device orplant in order that correct processing of the jobs J1 . . . J3 isensured. These actions A1 . . . Ax are created with a start time and thecorresponding dependencies on the basis of the simulation rules of thesolution algorithm 13 as necessary, when called by using the procedurecontrol unit 17. The actions A1 . . . Ax are started at the computingtime where they check their dependencies. Such a check on thedependencies, for example in the case of a semiconductor productiondevice, means that a so-called handler existing there can only carry outplacement in a specific module if a cover existing on the module, forexample, has been opened previously. The actual action is only triggeredif the check on all dependencies has been successful. Overall, a highlymodular solution is therefore created in which large parts of theapplication can be utilized again and again for all possible usagescenarios in so-called job scheduling, in particular in the case of theconsistent use of object-oriented development paradigms. Only therespective plant-specific details such as the individual actions(handler actions, module actions, etc.), the simulation environments forthe resources, and the solution algorithm have to be formulated in aconcrete manner for the respective use.

FIG. 2 shows a schematic representation of a system for controlling jobsof a production device 3 which is connected to an automation system 10.The automation system 10 includes a stored program control unit 2, anoperating and monitoring system 1, and also a data processing device 4on which a job control program 9 can be executed. The job controlprogram 9 includes a simulated image 6 of the real production device 3,an algorithm 8, and also a user interface 7. The user interface 7 isconnected via a data link 5, for example an OPC (Open Process Control),to the operating and monitoring system 1 and via said operating andmonitoring system to the stored program control unit 2, and via saidstored program control unit in turn to the production device 3. Theproduction device involves in particular a semiconductor productiondevice, for example a so-called wetbench. The production device 3 ischaracterized by waiting jobs J1 . . . Jn, and also existing modules(resources) R1 . . . Rn, and also by a manipulation device R0 as afurther resource.

With regard to the functioning of the job control program 9 on the dataprocessing device 4, reference is made to the description relating toFIG. 1. As the starting point for the job control for the productiondevice 3, for example a wetbench from the domain of the semiconductorindustry, the individual jobs J1 . . . Jn should be guided and managedin such a way that an optimum throughput of the production device 3 canbe achieved. In this respect, the jobs J1 . . . Jn should be managed andcontrolled in the production device 3 in such a way that the individualresources R0 . . . Rn can be utilized in the most efficient mannerpossible and at the same time the shortest possible running time of thejobs J1 . . . Jn can be expected. In this respect, the individual jobsJ1 . . . Jn can consist of various part stages, so-called tasks T1 . . .T13, T21 . . . T23, where each stage is effected by means of animplementing operation of resource R1 . . . Rn. In line with theschematic representation of the production device 3 in FIG. 2, the jobsJ1 . . . Jn can therefore possess a different number of stages andsequences. This problem of optimum utilization is solved with the aid ofthe job-shop scheduling program 9 which can be executed on the dataprocessing device 4 together with the approach explained in connectionwith FIG. 1.

To summarize, the following advantages can be asserted for the proposedmethod:

-   -   Separation of the general scheduling problem from concrete        optimization methods; consequently, a simpler exchange of the        mathematical parts can be effected, which in turn allows a        component-oriented plant configuration and modification.    -   Due to the independence of dispatcher and scheduler, local        calculation of the individual parts can be effected. Distributed        computer architectures can therefore be used, or the optimum        scheduling of the waiting jobs can be effected without        restrictions by the dispatcher. Previous plants only possess a        limited “computing window” since the results from the scheduler        also flow directly into the dispatcher.    -   Forward-planning operations and responses can already be        determined in advance through the compilation of an action list        which contains all the actions up to the final evacuation of the        plant.    -   Defective situations are identified by the fact that the        situation is evaluated continuously and new actions are created        for the elimination/bypassing of bottlenecks/problems.        Similarly, situations which cannot be solved are already        identifiable in advance with the result that a certain advance        warning time exists for the operator of the plant.    -   The use of object-oriented development paradigms makes it        possible to achieve simple modularization, scaling and        modification in a short period, since the main components remain        unaffected.    -   The consistent separation of general algorithm and        machine-specific simulations makes it possible to effect simple        exchangeability, which can also be adapted dynamically to the        running time in a complex system as necessary.

Starting from the problem, a consistent abstraction was necessary inorder to structure the method in a generally valid manner. Results ofindependent components (scheduler, dispatcher, actions) can thereforenow be used for the purposes of solving the overall problem. Thesolution is no longer based mainly on a purely mathematical description;instead, a general solution to the job-shop scheduling problem isobtained with the aid of simulation techniques. Mathematical componentsonly continue to play a role in the case of the pure optimization, andcan be exchanged without difficulty.

Moreover, it is not only current problems which are disclosed; instead,the use of the simulation up to the final “evacuation”/target state alsoidentifies future sources of malfunctions.

To summarize, the invention therefore relates to a system 9 and also amethod for controlling jobs J1 . . . Jn of a production device 3. Toenable an analysis of a current situation, the planning of the necessaryoperations, and also their implementation and monitoring independentlyof mathematical routines for optimizing the throughput, a simulatedimage SR1 . . . SR3, SJ1 . . . SJ3 is formed starting from an initialsituation 11 based on real resources R1 . . . R3 and real jobs J1 . . .J3, a possible sequence 15 of the jobs J1 . . . Jn is optimized on thebasis of the initial situation 11 with regard to existing resources R1 .. . Rn and existing jobs J1 . . . Jn with the aid of an optimizationalgorithm 12, and the production device 3 is controlled with the aid ofa solution algorithm 13 in such a way that a target state 14 isascertained by simulating the necessary operations of the productiondevice 3.

1.-10. (canceled)
 11. A system for controlling jobs of a productiondevice, comprising a data processing device, wherein the data processingdevice comprises: a planning mechanism for determining a possibleoptimum sequence of the jobs on the basis of an initial situation withregard to existing resources and existing jobs with the aid of anoptimization algorithm; and a procedure control unit for coordinatingthe control of the production device with the aid of a solutionalgorithm, which is provided for ascertaining a target state bysimulating the necessary operations of the production device.
 12. Thesystem according to claim 11, further comprising: a first mechanism forgenerating an image of the initial state of the production device withregard to existing resources and existing jobs.
 13. The system accordingto claim 11, wherein the production device is a manufacturing machine, aproduction machine, a manufacturing plant, and/or a production plant.14. The system according to claim 12, wherein the production device is amanufacturing machine, a production machine, a manufacturing plant,and/or a production plant.
 15. The system according to claim 11, whereinthe solution algorithm is provided for verifying the possible optimumsequence of the jobs determined by the planning mechanism.
 16. Thesystem according to claim 12, wherein the solution algorithm is providedfor verifying the possible optimum sequence of the jobs determined bythe planning mechanism.
 17. The system according to claim 13, whereinthe solution algorithm is provided for verifying the possible optimumsequence of the jobs determined by the planning mechanism.
 18. Thesystem according to claim 11, wherein the planning mechanism is providedfor coordinating the starting of waiting jobs on the basis of thecurrent situation image.
 19. The system according to claim 18, whereinthe planning mechanism is provided for coordinating the starting ofwaiting jobs on the basis of the current situation image and with theaid of the optimization algorithm.
 20. The system according to claim 12,wherein the planning mechanism is provided for coordinating the startingof waiting jobs on the basis of the current situation image.
 21. Thesystem according to claim 13, wherein the planning mechanism is providedfor coordinating the starting of waiting jobs on the basis of thecurrent situation image.
 22. The system according to claim 15, whereinthe planning mechanism is provided for coordinating the starting ofwaiting jobs on the basis of the current situation image.
 23. A methodfor controlling jobs of a production device, comprising: creating asimulated image regarding resources and jobs, wherein the creating ofthe simulated image is on the basis of an initial situation based onexisting resources and existing jobs; creating a possible optimumsequence of jobs on the basis of the initial situation with regard toexisting resources and existing jobs with the aid of an optimizationalgorithm; and controlling the production device with the aid of asolution algorithm in such a way that a target state is ascertained bysimulating the necessary operations of the production device.
 24. Themethod according to claim 23, wherein a stage where a possible optimumsequence of the jobs is created on the basis of the initial situationwith regard to existing resources and existing jobs with the aid of theoptimization algorithm is carried out multiple times.
 25. The methodaccording to claim 23, wherein the solution algorithm attempts, on thebasis of a given simulated situation, to achieve a predefinable targetstate of the production device by simulating the necessaryoperations/stages.
 26. The method according to claim 23, whereinforward-planning operations and responses are determined in advancethrough the compilation of an action list which contains all the actionsup to the final depletion of the production device.
 27. The methodaccording to claim 23, wherein defective situations are identified bycontinuously evaluating the situation images and new actions are createdfor eliminating or bypassing the defective situations.